Challenges in Conservation of Heritage Structures

International Journal of Latest Technology in Engineering, Management & Applied Science (IJLTEMAS)
2nd
Special Issue on Engineering and Technology | Volume VI, Issue VIS, June 2017 | ISSN 2278-2540
www.ijltemas.in Page 34
Challenges in Conservation of Heritage Structures
Mahipal Burdak1
, A K Gupta2
, D K Singhal3
1&2
Department of Structural Engineering, MBM Engineering College, JNV University Jodhpur, Rajasthan, India
3
Project Director, RSRDC Ltd Bikaner, Rajasthan, India
Abstract- Rajasthan is the most beautiful and vibrant state of
India. The unique characteristic of its architecture is very
popular in the whole world. The Rajasthan architecture is
significantly depend on Rajput architecture school which was
mixture of mughal and Hindu structural design. Grand havelis,
astonishing forts and elaborately carved temples are the vital
portion of architectural heritage of Rajasthan. Few of most
striking and splendid forts along with palaces with parched
Aravali land clearly depicts history of Rajasthan’s celebrated
heritage. Almost every city of the spectacular desert land
Rajasthan is lined with fabulous forts and palaces built by
various rulers and architects. These forts and palaces were
generally built outside the walled city over the high hills to
protect the city
The state of Rajasthan hosts few of splendid palaces and forts of
the whole world. Ornamented havelis, elaborately carved
temples and also magnificent forts are section of the Rajasthan’s
architectural heritage. The artistic builders designed major
architectural styles which are located in cities like Jaisalmer,
Udaipur, Jaipur and Jodhpur. The most significant architectural
designs in Rajasthan include Jantar Mantar, Dilwara Temples,
Lake Palace Hotel, and City Palaces, Chittorgarh Fort, Deeg
palace and Jaisalmer Havelis.
The glory is well conserved in the Rajasthan and in the majestic
forts and palaces. Enduring the unmerciful desert winds and
oppressing heat of the scorching sun, they have stood unshakable
against many-a-sieges and have provided protection to the rulers
in their time of conflict. Now, they have been opened to the
tourists who come here to see a wonderful presentation of their
rich heritage and splendid artistic architecture. Many of these
forts and palaces retain their old allure and ritual. Some of the
royal residences have been now turned into heritage hotels,
where the visitors can still experience the magic of India's
imperial past. Important Artifacts of Rajasthan Architecture
are: Havelis, Chhatris, Jharokhas, and Stepwells.
Keywords- Heritage Architecture, forts, havelis, Chhatris,
Jharokhas.
I. BASIC NEED OF HERITAGE CONSERVATION
eritage links us to history, the beautiful past we inherited
to preserve and transfer to our next generations
Heritage generally gives us a sense of our past and of our
cultural identity. Some researchers predicted very alarming
data regarding the survival of old heritage buildings. Load
bearing behavior of the Historic structures is very complex
due to continuous intrusion between various elements. The
main load is the dead load with wind and earthquake. The
behavior of these structures change with decay of material and
the cracks developed may even alter load path. Here a brief
scenario of heritage buildings and their structural aspects are
discussed including technical research activity, survey of
structures, structural behavior, and decay problems in
materials, safety evolution and structural damages.
After the Second World War the problem of rebuilding
and reconstructing the demolished Historic buildings appeared
worldwide. The complex load carrying behavior is due to
massive and continuous interaction between various structural
elements e.g. domes, vaults, arches and pillars. The structural
resistance depends preliminarily on two factors: the geometric
features of the structures and characteristic strengths of the
materials used.
II. EXPERIMENTAL RESEARCH FOR
CONSERVATION
The study of structure begins by mapping visible damage.
Survey drawings should map different kinds of materials,
noting any decay and any structural irregularities and damage,
paying particular attention to crack patterns and crushing
phenomena. Geometric irregularities can be the result of
previous deformations, which can indicate the junction
between different building phases or alterations to the fabric.
It is important to discover how the environment may be
damaging a building, since this can be exacerbated by poor
original design and/or workmanship (e.g. lack of drainage,
raising dampness, and vegetation), the use of unsuitable
materials and/or by poor subsequent maintenance.
Observation of areas where damage is concentrated as a result
of high compression (zones of crushing) or high tensions
(zones of cracking or the separation of elements) and the
direction of the cracks, together with an investigation of soil
conditions, may indicate the causes of damage.
The general laydown of technical activities for
conservation of such heritage structure includes, Identification
of historic materials (masonry-binding brick and fieldstone,
plaster, paint receiving layer, painted layer, and protective
layer etc), Identification of historic techniques, Damages,
deterioration or alteration of historic materials, Substantiation
and selection of conservation materials and methods,
Recommendations for the conservation-restoration works,
Inspection of the quality of conservation works.
Different methods of research on conservation of heritage
structure are: chemical analysis, Petro graphical -
H

2nd
Mineralogical, X-ray diffraction, spectral,
chromatographically, micro-chemical analysis, analysis of
pigments and organic bindings, artificial aging; biological
mycological research; physical research of building materials;
monitoring of microclimate regime of some historic buildings.
The practice is based on the composition of historic materials,
the existing physical condition or the character of destruction,
and on the principle of reversibility. These were clubbed
together with the technologists of restoration when applying
all the new methods.
The schedule of tests should be based on preliminary
phenomena views which are important to understand. Tests
usually aim to identify the mechanical (strength, deformability
etc.), physical (e.g. porosity) and chemical (e.g. composition)
characteristics of the materials, stresses / deformations of the
structure and the presence of any discontinuities within the
structure. As a rule, the schedule of tests should be divided
into stages, starting with the acquisition of basic data,
followed by a more detailed examination with tests based
upon an assessment of the implications of the initial data.
Non-destructive tests should be preferred to destructive
testing that involve any alterations to a structure. If NDTs are
not sufficient then it is necessary to assess by opening up the
structure in terms of reduced structural intervention against
the loss of culturally significant material. Tests should always
be carried out by experts to gauge their reliability correctly
and the assess implication of test data carefully. If possible
different NDT methods should be used and the results should
be compared.
III. STRUCTURAL BEHAVIOR
The behavior of any structure is influenced by three main
factors: the shape & the connections of the structure, the
construction materials and the forces, accelerations and
deformation, but before going to these details we have to
understand the mechanism of Decay first.
Restorers and art historians who were working with
architectural monuments in the 1960ies observed that many
historic monuments seemingly deteriorated at a much higher
Rate than it should have been expected only by natural
ageing. This effect could be visualized impressively in
comparative studies of documents that showed the
preservation state of some monuments at the beginning of the
20th century and approx. 60 years later It was concluded that
if there will not take place dramatic changes to the quality of
the Atmospheric environment - which were supposed to be
the main cause of the observed Changes - we will lose by the
end of the century a substantial part of our cultural heritage. In
1975 Feilden estimated that by the end of the century only
10% of the architectural heritage will “survive”, 1989 he gave
a more “optimistic” estimation, saying that hopefully it will be
more than 20%. To a similar conclusion came Winkler 1973,
who included results of many different studies on stone
deterioration (time lapse) and concluded that most of the stone
surfaces should be strongly deteriorated by the end of the 20th
century.
It was well understood, that scientific research is
necessary to understand the processes of deterioration of
materials and also to develop methods for rehabilitation and
conservation of the endangered heritage. Measures initiated
on pure empirical knowledge are certainly a good prevention,
but they do not guarantee success. On the other hand pure
scientific research gives clear results, however often fails,
when applied in practice. The main achievement of the years
lying now behind us, was the creation of an interdisciplinary
cooperation of all persons and bodies that integrated both –
scientific and practical experience. For the first time many
different disciplines from science, humanities, architecture,
engineering and others came together and tried to find
solutions for problems that in the past were thought to be
problems only of one of these groups respectively. This
cooperation needed several years of intensive exchange and
discussions and it seems that it started to work now. It is not
possible to give here an overview of all activities and
achievements that have been done in Germany for the
protection of historic monuments and the specific research for
a better understanding of their decay processes. Evidently the
whole variety of historic building structures and other
monuments consisting out of a variety of stone material,
metals, brick structures and many other different cultural
materials do behave in their environment differently in detail
IV. DIAGNOSIS & SAFETY EVOLUTION
Diagnosis and safety evaluation of the structure are two
consecutive and related stages on the basis of which the
effective need for and extent of treatment measures are
determined. Evaluation of the safety of the building should be
based on both qualitative (as documentation, observation etc.)
and quantitative (as experimental, mathematical etc.) methods
that take into account the effect of the phenomena on
structural behavior. Any assessment of safety is seriously
affected by two types of problem, the uncertainty attached to
data (actions, resistance, deformations, etc.), laws, models,
assumptions, etc. used in the research; the difficulty of
representing real phenomena in a precise way. It therefore
seems reasonable to try different approaches, each giving a
separate contribution, but which when combined produce the
best possible „verdict‟ based on the data at our disposal.
The diagnosis is to identify the causes of damage and
decay, on the basis of the acquired data. Which cover the
historical analysis, qualitative analysis and quantitative
analysis, which includes both mathematical modeling and
testing.
However, safety evaluation is also a difficult task because
methods of structural analysis used for new construction may
be neither accurate nor reliable for historic structures and may
result in inappropriate decisions. This is due to such factors as

2nd
the difficulty in fully understanding the complexity of an
ancient building or monument, uncertainties regarding
material characteristics, the unknown influence of previous
phenomena (for example soil settlements), and imperfect
knowledge of alterations and repairs carried out in the past.
Therefore, a quantitative approach based on mathematical
models cannot be the only procedure to be followed. As with
the diagnosis, qualitative approaches based on historical
research and on observation of the structure should also be
used. A fourth approach based on specific tests may also be
useful in some situations.
V. NON STRUCTURAL ELEMENT EXPERIMENTAL
STUDY
Photo-1 shows the marvelous work of Ekthamba Mahal in
Mandore garden Jodhpur. It is a three story structure with
octagonal plan. Decorative arches packed with stone Jalies
make it airy. Jalies are damaged but the quantum of damage
varies 1% to 5%. These jalies are very old and has cracks in
its thickness.
Replacement of complete jalies is neither cost effective
nor follows the conservation ethic, the part replacement is
difficult as there is progressive failure in fitting parts.
PHOTO-1 Ekthamba Mahal
Requirements of Traditional Mortar
Repair mortars are needed for replacing mortar in damaged or
severely weathered masonry mortar joints, for reconstruction
of deteriorated masonry, and for renewal of rendering. The
main components in a mortar mix are sand, binder and water.
Additional material may be added to modify the properties or
appearance of the mortar.
Repair mortars should be durable, practical in application,
and without negative effect on the durability of the existing
masonry heritage structure. Mortar should be considered
„sacrificial‟ since it is easier to repair mortar joints than
replace masonry units. Photo-2 shows conservation work with
traditional practice.
PHOTO-2 Conservation Work on Fort Wall
Durability is not only dependent on the mortar mix but
also on how it is installed and cured, on the compatibility
between the masonry unit and the mortar, and on the severity
of the environmental exposure, which in turn depends on
weather, design details, construction practice, operation, and
maintenance. The general principle “the stronger the
better”can lead damage to the masonry or shortened mortar
service life in heritage structures. Photo-3 of famous Salem
Sing Ki Haveli Jaisalmer where for repair cement mortar was
applied as against the traditional mortar which was stronger
than required and caused failure due to its incompatibility in
fabric & strength. The typical performance requirements are:
 Mortar should be no stronger than needed for the
structural and durability requirements of the
masonry. The long-term compressive strength should
be lower than that of the existing masonry units and
similar or lower in strength than the existing bedding
mortar. Unfortunately although the mortar itself may
become more durable it can have a negative effect on
the performance of the masonry as a whole.
 Water absorption and vapor transmission rates
should be similar to or greater than those of the
existing mortar and masonry units.
 Full contact between repair mortar and masonry units
should be well ensured.
 A lower strength mortar will also tend to be “soft” or
more flexible, a property that permits the mortar to
respond to small differential movement without
cracking.
 Cracks allow water ingress into the assembly which
can lead to freeze-thaw damage in cold weather. In
the spirit of sustainability and reversibility, low
strength mortars will also be easier to remove in
future maintenance and repairs.

2nd
PHOTO-3 Salem Sing Ki Haveli
Challenges in Mortar Selection-
 Original mortar materials are no longer available.
And difficult to determine the exact composition and
properties of the existing mortar.
 Issues of historic authenticity. The repair mortar
should correspond to the original one.
 Many of the materials and techniques for producing
and applying traditional mortars were lost and
substitutes may have to be found and techniques
learned again.
 Traditional mortars, usually of much lower strength
than modern mortars.
 Appropriate laboratory and site test procedures are
needed for the evaluation of repair mortars.
Lime Dhar for Parkota wall of Sojat fort (Photo-7) being
done in traditional way where low strength mortar being used.
The process include reducing alkalinity of hydraulic lime by
changing water from slaking tank. Mixing in mill with surkhi
and old dismantled mortar from the same old work with brick
bats. In addition organic additives Gur & Gugal with Belgiri
are incorporated.
PHOTO-4 Lime Dhar
VI. STRUCTURAL ELEMENT EXPERIMENTAL STUDY
The transformation of the massive stonework of Romanesque
architecture into the delicate tracery of the Gothic presents
clear evidence of the powerful logic of the trial and error
methods employed by the medieval builders. Without
mathematical theories or predictive methods, but with great
geometrical skill, Gothic builders learned to fashion stone - a
material limited to receiving compressive forces and requiring
careful fitting - into ribs and vaults that display some
understanding of the actions of forces within the structure.
The inside of celling of Ajeet Singh Deval (Photo-5) at
Mandore. The structure consisting mainly, the skeleton of
piers, buttresses, arches and ribbed vaulting can be considered
the splendor of the art of cutting stone that looks fragile for its
size and heavy enough to doubt for the structural stability.
PHOTO-5 Ajeet Singh Deval
At the present stage of knowledge, numerical simulations are
fundamental to provide insight into the structural behavior and
to assess/retrofit existing masonry structures. Nevertheless,
the step towards the development of reliable and accurate
numerical models cannot be performed without a thorough
material description and a proper validation by comparison
with a significant number of experimental results. This means
that carefully, deformation controlled experiments in large-
scale masonry tests, small masonry samples and masonry
components are necessary. So for accurate structural analysis
material properties of the existing structure are required
without hurting the monument. The nondestructive methods
of UPV are being applied in Gadisar Prol Jaisalmer (Photo-6)
& Terrace at (Photo-7) third floor in Patvon Ki Haveli where
wooden roofing has been sandwiched between lime Dhar &
stucco work evaluate to engineering properties of these
monuments which is virtually absent in the masonry
literature.

2nd
PHOTO-6 Gadisar Prol Jaisalmer
PHOTO-7 Gadisar Prol Terrace
Challenges in Analysis of Heritage Structures
The problems related to the analysis of ancient constructions
are: sometimes the geometry is usually missing, as shown in
Photo-8 of Rani Mahal in Sojat fort Pali where the
constitution of the inner core of the structural elements is
unknown, a complete mechanical characterization of the
materials utilized is hardly possible, the sequence of
construction is not documented and the building processes
vary substantially from one period to another as well as from
one site to another. Nevertheless, it is believed that
sophisticated numerical tools are of much importance for the
process of building knowledge about the structural behavior
of the constructions and for sensitivity studies about material
parameters.
PHOTO 8 Rani Mahal Sojat
The durability of structure is affected by environmental
factors such as wind, frost, rain, heat, storm, vapor &
moisture. In the case of this monument situated inside Gadisar
lake Jaisalmer where all the factor enhancing to detoriate the
structure at a faster rate (Photo-9).
PHOTO-9 Gadisar lake Jaisalmer
All buildings deteriorate with time. The factors deciding the
rate of deterioration include initial status (design assumptions,
materials used and workmanship), age, quality of use,
environment, ground movement and quality of upkeep. At a
given time, depending on the above and other factors a
structure is in a state of deterioration. Under more severe
state, deterioration may turn into structural damages. The
decay are more prone to corners & discontinuities as chances
of physical intervention are augmented (Photo-19).
There may be damages irrespective of the state of
deterioration. Such causes are attributed to effects of
earthquake, flood, cyclone, fire, weapons effect of destruction
etc. The state of deterioration, indeed, contributes to these
short duration effects.
When one intervenes towards restoration it is a primary need
to examine the premises on which the initial design, material
selection and construction were based. It is necessary to
ascertain whether assumptions of load, environmental
exposure, soil bearing capacity etc. are still valid.
The scaling is formed in the inner side of the dome (Photo-10)
which has beautiful aries work, due to seepage from top, but
could not be scaled off as it will spoil the beautiful design of
aries work.Venice Charter and Burra Charter for guidance,
provisions are to be read, understood and applied in entirety.
Only such materials that are consistent with existing material
systems should be adopted. Only in very special/critical
situations a different/modified material may be used in a way
that it can be withdrawn without damaging the original system
(fabric). Interventions, particularly structural interventions,
and replacements should be explicit so that any viewer would
be able to discern between the original and the subsequent.

2nd
For example, use of cement is discouraged in restoration
/conservation of ancient monuments. In a stone wall
containing decorative panel while being restored would accept
only stones without motif.
In Kiradu Barmer (Photo-11) for groups of temples
conservation could not be carried out as the original quarries
are in Sindh Pakistan. And stone with similar fabric is not
available. Neither there are such distinctions like explicit or
implicit interventions as long as functional requirements are
not disturbed. And yet, there is to be caution about using new
material that cannot be withdrawn later
PHOTO-10 Top Dome
PHOTO-21 Kiradu Barmer
Earthquakes
Most of the heritage structures are unreinforced masonry
structures. Stone masonry construction generally shows very
poor seismic performance. Poor quality of mortar is the main
reason for the low tensile strength of rubble stone masonry.
Timber floor and roof structures are usually not heavy and
therefore do not induce large seismic forces. However, typical
timber floor structures are made of timber joists that are not
properly connected to structural walls. These structures are
rather flexible and are not able to act as rigid diaphragms. Due
to their large thickness, stone masonry walls are rather heavy
and induce significant seismic forces. This bhuj of Sonar fort
collapsed on 9.4.09 due to earthquake of very moderate
intensity of 5.3.This has been due to the fact that the structure
is free lump mass with almost no cohesion between masonry
blocks and being asymmetric on one axis as being semicircle.
Dynamic parameters of ancient structures are generally not
favorable from the viewpoint of the aseismic design. For
example the fundamental period of such type of structures
ranges between 0.10 – 0.30 s, i.e. they are very rigid. The
consequence is that such structures are much sensitive to
pulse type of loading. Stone and brick masonry both have
large specific mass.
VII. DISCUSSION
Very recently the scientific community has begun to show
interest in advanced testing (under displacement control) and
advanced tools of analysis for historical constructions.
The lack of experience in this field is alarming in
comparison with more advanced research fields like concrete,
soil, rock or composite mechanics. It is also advocated that
sophisticated and robust models for masonry structures are
currently available and can be successfully used for the
analysis of historical constructions.
Conservation of heritage structures is multi-disciplined
work involving knowledge of structural engineering in depth
with latest available technology in the industry, but this tool
has its dependence on material property like the property of
stone available in the concerned region and the mortar. The
property of stone as well as mortar changes with passing of
time and more important is that the masonry work in heritage
structures was traditional lime sand surki mortar with organic
additives like gur, gugal, methi, hemp and coconut etc in
combination of one or more with varying percentage.
The property of stone & mortar changes with time and
their today‟s value is very difficult to ascertain. To reach at
scientific values of their property & engineering characters
NDT and Ultra sound techniques are of importance.
Beside that the problem of Heritage structures their
accessibility becomes problem. When masonry structure is
subjected to lateral inertial loads during an earthquake, the
walls develop shear and flexural stresses. The strength of
masonry under these conditions often depends on the bond
between element and mortar which is quite poor in heritage
structures as lime mortars or mud mortars are used. A
masonry wall can also undergo in-plane shear stresses if the
inertial forces are in the plane of the wall, Shear failure in the
form of diagonal cracks is observed due to this. However,

2nd
catastrophic collapse takes place when the wall is subjected to
out-of-plane flexure.
In an ideal world, restoration strategies should be designed
to include the least intrusive methods and they should be
reversible. Wherever possible, they should also attempt to use
traditional materials that are similar to those used for the
original construction – and compatible with the masonry in
terms of movement accommodation etc.
VIII. CONCLUSION
Conservation of Heritage buildings is quite different from
new construction. Conservation needs preliminary study of
existing structure in detail and the stages it has passed in past.
Performing experiments can be highly sensitive. The burning
demand of today‟s societies is to carry out Restoration &
Conservation of these mighty structures. For that identifying
the damage, progress of damage, any immediate risk needing
attention and environmental effect is necessary. Modern
science has opened up scope by latest tools. Today strong
need is to have a compromise between Quantitative,
Qualitative and Historical analysis for restoration of historic
building and a model spectrum is required to be developed
giving due weightage to all variables for the value of
individual structure. Data collection has vital role to play for
conservation and requires very precise and scientific
involvement. Existing fabric has to be restored; new one
should be compatible and in resemblance with minimum
intervention to the old one. Heritage has always attracted
tourism nationally as well as internationally strengthening
local and national economy. Heritage may be categorized as
Monuments, Sites, Buildings, Artifacts, Cultural Landscape
and Intangible Heritage .Religious, Art History and
Architecture, Scientific and Technical, Nationalist, Domestic,
Economic and Development, Re-creational and Humanistic
are its paradigms.
Various international agencies independently, under UN
cover and national agencies, regional authorities and NGOS
are working in this field. There is need of active coordination
of all these administrative and executive agencies so that
uniformity in policy of conservation is formed. Under the
same cover techniques should be idealised for utilities on
regional bases and by facility to be provided to all concern
interested in matter via information-technology.
REFERENCES
[1]. Elvyra Veronika TELKSNIENE, Head of technical research
laboratory, The Centre of Cultural Heritage, Vilnius, Lithuania;
“Historic Materials and Their Diagnostic in Lithuania”
[2]. Acun S; Arioglue N “The evolution of lime mortars and plasters
with purpose of Conservation and Restoration”, ITU, Architecture
Faculty, Takisla Istumbul Turkey,Commission VI,WG VI/6 pp1-6
[3]. International Council of Monuments and Sites,
“Recommendations for the Analysis, Conservation and Structural
Restoration of Architectural Heritage”.
[4]. Stephan Fitz, “A Spotlight on the Present Situation at the
Beginning of the New Millennium” Saving Cultural Heritage in
Germany, a report.
[5]. Feiden, B.M., “The State of Europe‟s Architectural Heritage” a
proceeding on European Symposium.
[6]. Michoinova Dagmar “New Materials for the Protection of
Cultural Heritage State Institute for the Care of Historical
Monuments”, Technological Department, Valdstenjnske
[7]. Computer aided behavioral analysis of complex physical systems
applied to stone decay in monuments.
[8]. BÖHLER, Monica BORDAS VICENT, Guido HEINZ, Andreas
MARBS and Hartmut MÜLLER, High Quality Scanning and
Modeling of Monuments and Artifacts Wolfgang.
[9]. F. Summers a, N. Atalan a, N. Aydın a, O. Basagac, G. Uçar, a
Documentation of Archaeological Runs and Standing Monuments
using Photo-Rectification and 3D Modelling
[10]. Coldstream N. “Medieval Craftsmen: Masons and Sculptors”.
British Museum Press, London, 1990
[11]. CSA (Canadian Standards Association). 2004. “Mortar and Grout
for Unit Masonry.” CSA A179-04
[12]. ElGawady M, Lestuzzi P.M, Badoux A , “Review of
conventional seismic retrofitting techniques for URM” 13th
International Brick and Block Masonry Conference Amsterdam,
July 4-7, 2004
[13]. Feilden B.M., The State of Europe‟s Architectural Heritage: A
Personal View. in Science, Technology and European Cultural
Heritage: Proceedings of the European symposium, Bologna 1989,
Ed. N.S. Baer, C. Sabbioni, A. Sors
[14]. Gupta A.P. Formerly Professor, Department of Civil Engineering,
IIT, Kharagpur 20– SE201 NPCBEERM, MHA(DM) 1
CHAPTER 20 “Deterioration and damage in buildings.”
[15]. Maurenbrecher A.H.P. “Mortars for repair of traditional masonry”
NRCC-46903.
[16]. Saving Cultural Heritage in Germany A Spotlight t on the Present
Situation at the Beginning of the New Millennium Stephan Fitz
[17]. Winkler E.M., “Stone: properties, durability in men‟s
environment”, 1st edn. Springer, Berlin Heidelberg New York,
1973

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